Who else but HBO would have the audacity to commission a five-part, nearly-six-hour version of James M. Cain's period melodrama?

The way Kate Winslet’s name is displayed in enormous block letters — right before “Mildred Pierce” — provides key insight into how HBO operates, using this sort of extravagant exercise to market the channel. Who else, after all, would have the audacity to commission a five-part, nearly-six-hour version of James M. Cain’s period melodrama — enlisting not just Winslet to star, but surrounding her with a splendid cast that includes fellow Oscar winner Melissa Leo, Guy Pearce and Evan Rachel Wood? That the production proceeds deliberately becomes somewhat irrelevant. Because before it’s over, “Mildred” is big, beautiful and clearly not just any TV.

Those expecting a rehash of the 1945 Joan Crawford vehicle will need an attitude adjustment, since director Todd Haynes (who co-wrote the teleplay with Jon Raymond) has gone back to the source material. He also explores Depression-era class issues and mores with the same loving attention to intimate detail he brought to “Far From Heaven.”

This is, in short, not your grandma’s “Mildred,” though the fundamental building blocks remain the same. Divorced from her philandering husband (Brian F. O’Byrne) in the opening frames, Winslet’s Mildred is left to care for two young daughters. They include the spoiled Veda (first Morgan Turner, later Wood), whom Mildred dotes on, despite her oddly patrician and condescending attitude.

Struggling to make ends meet, Mildred becomes a waitress, and after considerable suffering, learns enough from observation to open her own restaurant. Along the way, she has affairs with her husband’s former partner, Wally (James LeGros), and the dashing Monty Beragon (Pearce), a pampered fop who eventually becomes Mildred’s “paid gigolo,” as he snidely puts it, when his own fortunes sour.

The central relationship, however, remains between Mildred and Veda, whose aspirations to become a concert pianist are dealt a setback, widening the strange rift between mother and daughter. “Haven’t I given you everything you ever wanted?” Mildred pleads.

Despite her improved finances, Mildred keeps being rebuffed in her desire to win Veda’s affections, a process Winslet conveys with a medley of heartbroken looks and pained, longing gazes. Wood is terrifically icy as Veda, though Turner’s performance — playing the character in her early teens — might be even creepier, when the girl’s manner seems even more imperious and otherworldly.

Haynes and his team capture the mood and look of 1930s Los Angeles (actually shot in New York) with painstaking intricacy. Seldom has more time been spent showing the particulars of preparing chicken or baking a pie in a major TV production.

Still, there’s ultimately method to his madness. After a plodding start, “Mildred” becomes increasingly absorbing. And while creative license to be more explicit isn’t always an asset, in this case — from Wally and Mildred’s fumbling trysts to her sensuous coupling with Monty — the effect is to render key moments and acts of betrayal more startling and powerful.

Scheduled over three weeks (the last two parts, airing together, total 2½ hours), the project unfolds in an unhurried manner unlike anything on TV except perhaps “Masterpiece” miniseries — and, indeed, has the feel of an Americanized version of a tony British costume drama.

For HBO, though, “Mildred Pierce” makes a statement culled from the old “It’s not TV” slogan: Not only has the pay channel attracted a world-class actress at the height of her powers and surrounded her with a gaudy cast, but the resulting production occupies a virtually uninhabited zone, far from the commercial demands of blockbuster theatricals or procedural TV dramas.

Seriously, devoting more than five hours to a three-hankie 1930s drama, tinged with underlying relevance about modern economic priorities and the class divide? For that alone, “Mildred Pierce” — just like its leading lady — seems calculated to plaster HBO’s own name far above the pack.

Mildred Pierce

HBO

Production

Filmed in New York by Killer Films and John Wells Prods., and presented in association with Metro-Goldwyn-Mayer. Executive producers, Christine Vachon, Pamela Koffler, John Wells, Todd Haynes; co-executive producer, Ilene S. Landress; director, Haynes; writers, Haynes, Jon Raymond; based on the novel by James M. Cain.